I actually believe we will see many that do not come from within either community. Outsiders will want to use the software but with a different governance model and distribution.
We will see which software gets updated with what features. That is going to determine what attracts other developers who want to delve into other projects.
Have you been following BravoCoin or their new project Re-Buzz? They are Steem forks with slick native apps but they were not an airdrop hardfork like Hive. Hive is so successful so far because of the airdrop and a few exchanges picking it up.